From 35f8eb0ae9779ef5a3b6b39b40cfac487adfee2d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Fri, 13 Jan 2017 15:33:20 +0100
Subject: [PATCH 01/17] position_jitter() gains seed argument

---
 R/position-jitter.r    | 15 ++++++++++-----
 R/utilities.r          | 10 ++++++++++
 man/position_jitter.Rd |  4 +++-
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/R/position-jitter.r b/R/position-jitter.r
index 8f65e7eca1..85dca8dc9e 100644
--- a/R/position-jitter.r
+++ b/R/position-jitter.r
@@ -13,6 +13,9 @@
 #'   jitter values will occupy 80\% of the implied bins. Categorical data
 #'   is aligned on the integers, so a width or height of 0.5 will spread the
 #'   data so it's not possible to see the distinction between the categories.
+#' @param seed An optional random seed to make the jitter reproducible.
+#'   Useful if you need to apply the same jitter twice, e.g., for a point and
+#'   a corresponding label.
 #' @export
 #' @examples
 #' # Jittering is useful when you have a discrete position, and a relatively
@@ -31,10 +34,11 @@
 #'   geom_jitter(width = 0.1, height = 0.1)
 #' ggplot(mtcars, aes(am, vs)) +
 #'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
-position_jitter <- function(width = NULL, height = NULL) {
+position_jitter <- function(width = NULL, height = NULL, seed = NULL) {
   ggproto(NULL, PositionJitter,
     width = width,
-    height = height
+    height = height,
+    seed = seed
   )
 }
 
@@ -48,13 +52,14 @@ PositionJitter <- ggproto("PositionJitter", Position,
   setup_params = function(self, data) {
     list(
       width = self$width %||% (resolution(data$x, zero = FALSE) * 0.4),
-      height = self$height %||% (resolution(data$y, zero = FALSE) * 0.4)
+      height = self$height %||% (resolution(data$y, zero = FALSE) * 0.4),
+      seed = self$seed
     )
   },
 
   compute_layer = function(data, params, panel) {
-    trans_x <- if (params$width > 0) function(x) jitter(x, amount = params$width)
-    trans_y <- if (params$height > 0) function(x) jitter(x, amount = params$height)
+    trans_x <- if (params$width > 0) function(x) with_seed(params$seed, jitter(x, amount = params$width))
+    trans_y <- if (params$height > 0) function(x) with_seed(params$seed, jitter(x, amount = params$height))
 
     transform_position(data, trans_x, trans_y)
   }
diff --git a/R/utilities.r b/R/utilities.r
index 0d93691676..18a3bba571 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -299,6 +299,16 @@ find_args <- function(...) {
 # global data
 dummy_data <- function() data.frame(x = NA)
 
+with_seed <- function(seed, code) {
+  if (!is.null(seed)) {
+    old_seed <- get0(".Random.seed", globalenv())
+    if (!is.null(old_seed)) {
+      on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
+    }
+  }
+  code
+}
+
 # Needed to trigger package loading
 #' @importFrom tibble tibble
 NULL
diff --git a/man/position_jitter.Rd b/man/position_jitter.Rd
index df8e8880a1..a0460e819b 100644
--- a/man/position_jitter.Rd
+++ b/man/position_jitter.Rd
@@ -4,7 +4,7 @@
 \alias{position_jitter}
 \title{Jitter points to avoid overplotting}
 \usage{
-position_jitter(width = NULL, height = NULL)
+position_jitter(width = NULL, height = NULL, seed = NULL)
 }
 \arguments{
 \item{width, height}{Amount of vertical and horizontal jitter. The jitter
@@ -15,6 +15,8 @@ position_jitter(width = NULL, height = NULL)
   jitter values will occupy 80\% of the implied bins. Categorical data
   is aligned on the integers, so a width or height of 0.5 will spread the
   data so it's not possible to see the distinction between the categories.}
+
+\item{seed}{An optional random seed to make the jitter reproducible.}
 }
 \description{
 Couterintuitively adding random noise to a plot can sometimes make it

From 9c9951e8ad0185f1de61583866803bf755861b6d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Wed, 25 Jan 2017 09:50:40 +0100
Subject: [PATCH 02/17] use only one with_seed() call

---
 R/position-jitter.r | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/R/position-jitter.r b/R/position-jitter.r
index 85dca8dc9e..d2443ab760 100644
--- a/R/position-jitter.r
+++ b/R/position-jitter.r
@@ -58,9 +58,9 @@ PositionJitter <- ggproto("PositionJitter", Position,
   },
 
   compute_layer = function(data, params, panel) {
-    trans_x <- if (params$width > 0) function(x) with_seed(params$seed, jitter(x, amount = params$width))
-    trans_y <- if (params$height > 0) function(x) with_seed(params$seed, jitter(x, amount = params$height))
+    trans_x <- if (params$width > 0) function(x) jitter(x, amount = params$width)
+    trans_y <- if (params$height > 0) function(x) jitter(x, amount = params$height)
 
-    transform_position(data, trans_x, trans_y)
+    with_seed(params$seed, transform_position(data, trans_x, trans_y))
   }
 )

From b789ed395e347b253e5edc3ae6fa802d89a9d6fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Wed, 25 Jan 2017 15:55:07 +0100
Subject: [PATCH 03/17] use mode = 'integer'

---
 R/utilities.r | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/R/utilities.r b/R/utilities.r
index 18a3bba571..bb8bd3f3af 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -301,7 +301,7 @@ dummy_data <- function() data.frame(x = NA)
 
 with_seed <- function(seed, code) {
   if (!is.null(seed)) {
-    old_seed <- get0(".Random.seed", globalenv())
+    old_seed <- get0(".Random.seed", globalenv(), mode = "integer")
     if (!is.null(old_seed)) {
       on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
     }

From 5bfcb597bfb8d624336b735118c864d5300c1236 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Wed, 25 Jan 2017 15:58:42 +0100
Subject: [PATCH 04/17] actually set seed

---
 R/utilities.r | 1 +
 1 file changed, 1 insertion(+)

diff --git a/R/utilities.r b/R/utilities.r
index bb8bd3f3af..06382f3e9c 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -305,6 +305,7 @@ with_seed <- function(seed, code) {
     if (!is.null(old_seed)) {
       on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
     }
+    set.seed(seed)
   }
   code
 }

From f227475c67ba05588aebae3dfbaa30f8d33140c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Fri, 3 Feb 2017 00:01:11 +0100
Subject: [PATCH 05/17] fixed seed by default

---
 R/position-jitter.r    | 6 ++++--
 man/position_jitter.Rd | 8 ++++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/R/position-jitter.r b/R/position-jitter.r
index d2443ab760..d421af7ba4 100644
--- a/R/position-jitter.r
+++ b/R/position-jitter.r
@@ -13,9 +13,11 @@
 #'   jitter values will occupy 80\% of the implied bins. Categorical data
 #'   is aligned on the integers, so a width or height of 0.5 will spread the
 #'   data so it's not possible to see the distinction between the categories.
-#' @param seed An optional random seed to make the jitter reproducible.
+#' @param seed A random seed to make the jitter reproducible.
 #'   Useful if you need to apply the same jitter twice, e.g., for a point and
 #'   a corresponding label.
+#'   The random seed is reset after jittering,
+#'   use `NULL` to use the current random seed and avoid resetting.
 #' @export
 #' @examples
 #' # Jittering is useful when you have a discrete position, and a relatively
@@ -34,7 +36,7 @@
 #'   geom_jitter(width = 0.1, height = 0.1)
 #' ggplot(mtcars, aes(am, vs)) +
 #'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
-position_jitter <- function(width = NULL, height = NULL, seed = NULL) {
+position_jitter <- function(width = NULL, height = NULL, seed = 4L) {
   ggproto(NULL, PositionJitter,
     width = width,
     height = height,
diff --git a/man/position_jitter.Rd b/man/position_jitter.Rd
index a0460e819b..6d36c339a1 100644
--- a/man/position_jitter.Rd
+++ b/man/position_jitter.Rd
@@ -4,7 +4,7 @@
 \alias{position_jitter}
 \title{Jitter points to avoid overplotting}
 \usage{
-position_jitter(width = NULL, height = NULL, seed = NULL)
+position_jitter(width = NULL, height = NULL, seed = 4L)
 }
 \arguments{
 \item{width, height}{Amount of vertical and horizontal jitter. The jitter
@@ -16,7 +16,11 @@ position_jitter(width = NULL, height = NULL, seed = NULL)
   is aligned on the integers, so a width or height of 0.5 will spread the
   data so it's not possible to see the distinction between the categories.}
 
-\item{seed}{An optional random seed to make the jitter reproducible.}
+\item{seed}{A random seed to make the jitter reproducible.
+Useful if you need to apply the same jitter twice, e.g., for a point and
+a corresponding label.
+The random seed is reset after jittering,
+use `NULL` to use the current random seed and avoid resetting.}
 }
 \description{
 Couterintuitively adding random noise to a plot can sometimes make it

From d6122768de7342db8d7ec86a1c6a03beaf9df9a5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Fri, 3 Feb 2017 00:02:09 +0100
Subject: [PATCH 06/17] NEWS

---
 NEWS | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/NEWS b/NEWS
index 12746fc39f..54284565c7 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,6 @@
+* `position_jitter()` gains a `seed` argument that allows specifying a random
+  seed for reproducible jittering (#1996, @krlmlr).
+
 ggplot2 1.0.1
 ----------------------------------------------------------------
 

From b988c0ab7e00d7ecee2c4639b957e616c2a6caeb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Sat, 4 Feb 2017 18:29:36 +0100
Subject: [PATCH 07/17] support seed = NA, which is now the default

in this mode, the random seed is not changed, but reset after processing
---
 R/position-jitter.r    | 8 +++++---
 R/utilities.r          | 4 +++-
 man/position_jitter.Rd | 8 +++++---
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/R/position-jitter.r b/R/position-jitter.r
index d421af7ba4..7f7a2fcc20 100644
--- a/R/position-jitter.r
+++ b/R/position-jitter.r
@@ -16,8 +16,10 @@
 #' @param seed A random seed to make the jitter reproducible.
 #'   Useful if you need to apply the same jitter twice, e.g., for a point and
 #'   a corresponding label.
-#'   The random seed is reset after jittering,
-#'   use `NULL` to use the current random seed and avoid resetting.
+#'   The random seed is reset after jittering.
+#'   If `NA` (the default value), the current random seed is used.
+#'   Use `NULL` to use the current random seed and also avoid resetting
+#'   (the behavior of \pkg{ggplot} 2.2.1 and earlier).
 #' @export
 #' @examples
 #' # Jittering is useful when you have a discrete position, and a relatively
@@ -36,7 +38,7 @@
 #'   geom_jitter(width = 0.1, height = 0.1)
 #' ggplot(mtcars, aes(am, vs)) +
 #'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
-position_jitter <- function(width = NULL, height = NULL, seed = 4L) {
+position_jitter <- function(width = NULL, height = NULL, seed = NA) {
   ggproto(NULL, PositionJitter,
     width = width,
     height = height,
diff --git a/R/utilities.r b/R/utilities.r
index 06382f3e9c..93ad7a222c 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -305,7 +305,9 @@ with_seed <- function(seed, code) {
     if (!is.null(old_seed)) {
       on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
     }
-    set.seed(seed)
+    if (!is.na(seed)) {
+      set.seed(seed)
+    }
   }
   code
 }
diff --git a/man/position_jitter.Rd b/man/position_jitter.Rd
index 6d36c339a1..4a377b598a 100644
--- a/man/position_jitter.Rd
+++ b/man/position_jitter.Rd
@@ -4,7 +4,7 @@
 \alias{position_jitter}
 \title{Jitter points to avoid overplotting}
 \usage{
-position_jitter(width = NULL, height = NULL, seed = 4L)
+position_jitter(width = NULL, height = NULL, seed = NA)
 }
 \arguments{
 \item{width, height}{Amount of vertical and horizontal jitter. The jitter
@@ -19,8 +19,10 @@ position_jitter(width = NULL, height = NULL, seed = 4L)
 \item{seed}{A random seed to make the jitter reproducible.
 Useful if you need to apply the same jitter twice, e.g., for a point and
 a corresponding label.
-The random seed is reset after jittering,
-use `NULL` to use the current random seed and avoid resetting.}
+The random seed is reset after jittering.
+If `NA` (the default value), the current random seed is used.
+Use `NULL` to use the current random seed and also avoid resetting
+(the behavior of \pkg{ggplot} 2.2.1 and earlier).}
 }
 \description{
 Couterintuitively adding random noise to a plot can sometimes make it

From 6f20e6ccfe5b06ea44037d252957c88532084c56 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Sat, 4 Feb 2017 18:36:43 +0100
Subject: [PATCH 08/17] with_seed() always initializes RNG

---
 R/utilities.r | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/R/utilities.r b/R/utilities.r
index 93ad7a222c..40e0f3421b 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -301,10 +301,13 @@ dummy_data <- function() data.frame(x = NA)
 
 with_seed <- function(seed, code) {
   if (!is.null(seed)) {
-    old_seed <- get0(".Random.seed", globalenv(), mode = "integer")
-    if (!is.null(old_seed)) {
-      on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
+    old_seed <- get_seed()
+    if (is.null(old_seed)) {
+      # Trigger initialisation of RNG
+      runif(1L)
+      old_seed <- get_seed()
     }
+    on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
     if (!is.na(seed)) {
       set.seed(seed)
     }
@@ -312,6 +315,10 @@ with_seed <- function(seed, code) {
   code
 }
 
+get_seed <- function() {
+  get0(".Random.seed", globalenv(), mode = "integer")
+}
+
 # Needed to trigger package loading
 #' @importFrom tibble tibble
 NULL

From a00407e6640a4bf2a7c6223b8fa8e7b97d578f78 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Sat, 4 Feb 2017 20:33:50 +0100
Subject: [PATCH 09/17] added example

---
 R/position-jitter.r    | 6 ++++++
 man/position_jitter.Rd | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/R/position-jitter.r b/R/position-jitter.r
index 7f7a2fcc20..6f647e4f67 100644
--- a/R/position-jitter.r
+++ b/R/position-jitter.r
@@ -38,6 +38,12 @@
 #'   geom_jitter(width = 0.1, height = 0.1)
 #' ggplot(mtcars, aes(am, vs)) +
 #'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
+#'
+#' # Reproducible jitter by default
+#' ggplot(mtcars, aes(am, vs)) +
+#'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
+#'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1),
+#'     color = red, aes(am + 0.2, vs + 0.2))
 position_jitter <- function(width = NULL, height = NULL, seed = NA) {
   ggproto(NULL, PositionJitter,
     width = width,
diff --git a/man/position_jitter.Rd b/man/position_jitter.Rd
index 4a377b598a..1afb0ad35e 100644
--- a/man/position_jitter.Rd
+++ b/man/position_jitter.Rd
@@ -46,6 +46,12 @@ ggplot(mtcars, aes(am, vs)) +
   geom_jitter(width = 0.1, height = 0.1)
 ggplot(mtcars, aes(am, vs)) +
   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
+
+# Reproducible jitter by default
+ggplot(mtcars, aes(am, vs)) +
+  geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
+  geom_jitter(position = position_jitter(width = 0.1, height = 0.1),
+    color = red, aes(am + 0.2, vs + 0.2))
 }
 \seealso{
 Other position adjustments: \code{\link{position_dodge}},

From f0d3e1a1afa42a3c12b628a6e409ed4ea2ad040a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Tue, 7 Feb 2017 12:37:39 +0100
Subject: [PATCH 10/17] extract function

---
 R/utilities.r | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/R/utilities.r b/R/utilities.r
index 40e0f3421b..b1d40e36b2 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -301,12 +301,7 @@ dummy_data <- function() data.frame(x = NA)
 
 with_seed <- function(seed, code) {
   if (!is.null(seed)) {
-    old_seed <- get_seed()
-    if (is.null(old_seed)) {
-      # Trigger initialisation of RNG
-      runif(1L)
-      old_seed <- get_seed()
-    }
+    old_seed <- get_valid_seed()
     on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
     if (!is.na(seed)) {
       set.seed(seed)
@@ -315,6 +310,16 @@ with_seed <- function(seed, code) {
   code
 }
 
+get_valid_seed <- function() {
+  seed <- get_seed()
+  if (is.null(seed)) {
+    # Trigger initialisation of RNG
+    runif(1L)
+    seed <- get_seed()
+  }
+  seed
+}
+
 get_seed <- function() {
   get0(".Random.seed", globalenv(), mode = "integer")
 }

From ae4f33c8eb22e781f210f4321cd53ee3a380c707 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Tue, 7 Feb 2017 12:37:51 +0100
Subject: [PATCH 11/17] fix and clarify example

---
 R/position-jitter.r    | 8 ++++----
 man/position_jitter.Rd | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/R/position-jitter.r b/R/position-jitter.r
index 6f647e4f67..b4c079a409 100644
--- a/R/position-jitter.r
+++ b/R/position-jitter.r
@@ -39,11 +39,11 @@
 #' ggplot(mtcars, aes(am, vs)) +
 #'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
 #'
-#' # Reproducible jitter by default
+#' # Create a jitter object for reproducible jitter:
+#' jitter <- position_jitter(width = 0.1, height = 0.1)
 #' ggplot(mtcars, aes(am, vs)) +
-#'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
-#'   geom_jitter(position = position_jitter(width = 0.1, height = 0.1),
-#'     color = red, aes(am + 0.2, vs + 0.2))
+#'   geom_point(position = jitter) +
+#'   geom_point(position = jitter, color = "red", aes(am + 0.2, vs + 0.2))
 position_jitter <- function(width = NULL, height = NULL, seed = NA) {
   ggproto(NULL, PositionJitter,
     width = width,
diff --git a/man/position_jitter.Rd b/man/position_jitter.Rd
index 1afb0ad35e..d7435f14cd 100644
--- a/man/position_jitter.Rd
+++ b/man/position_jitter.Rd
@@ -47,11 +47,11 @@ ggplot(mtcars, aes(am, vs)) +
 ggplot(mtcars, aes(am, vs)) +
   geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
 
-# Reproducible jitter by default
+# Create a jitter object for reproducible jitter:
+jitter <- position_jitter(width = 0.1, height = 0.1)
 ggplot(mtcars, aes(am, vs)) +
-  geom_jitter(position = position_jitter(width = 0.1, height = 0.1))
-  geom_jitter(position = position_jitter(width = 0.1, height = 0.1),
-    color = red, aes(am + 0.2, vs + 0.2))
+  geom_point(position = jitter) +
+  geom_point(position = jitter, color = "red", aes(am + 0.2, vs + 0.2))
 }
 \seealso{
 Other position adjustments: \code{\link{position_dodge}},

From 28b114b68b638f33b1c6d3297dbac664cf4649b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Tue, 7 Feb 2017 12:43:41 +0100
Subject: [PATCH 12/17] NA picks a random seed using sample.int()

---
 R/position-jitter.r    | 3 ++-
 R/utilities.r          | 5 +++--
 man/position_jitter.Rd | 3 ++-
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/R/position-jitter.r b/R/position-jitter.r
index b4c079a409..6b8350b299 100644
--- a/R/position-jitter.r
+++ b/R/position-jitter.r
@@ -17,7 +17,8 @@
 #'   Useful if you need to apply the same jitter twice, e.g., for a point and
 #'   a corresponding label.
 #'   The random seed is reset after jittering.
-#'   If `NA` (the default value), the current random seed is used.
+#'   If `NA` (the default value), the seed is initialised with a random value;
+#'   this makes sure that two subsequent calls start with a different seed.
 #'   Use `NULL` to use the current random seed and also avoid resetting
 #'   (the behavior of \pkg{ggplot} 2.2.1 and earlier).
 #' @export
diff --git a/R/utilities.r b/R/utilities.r
index b1d40e36b2..5cb065de79 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -303,9 +303,10 @@ with_seed <- function(seed, code) {
   if (!is.null(seed)) {
     old_seed <- get_valid_seed()
     on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
-    if (!is.na(seed)) {
-      set.seed(seed)
+    if (is.na(seed)) {
+      seed <- sample.int(2147483647L, 1L)
     }
+    set.seed(seed)
   }
   code
 }
diff --git a/man/position_jitter.Rd b/man/position_jitter.Rd
index d7435f14cd..ca6008001d 100644
--- a/man/position_jitter.Rd
+++ b/man/position_jitter.Rd
@@ -20,7 +20,8 @@ position_jitter(width = NULL, height = NULL, seed = NA)
 Useful if you need to apply the same jitter twice, e.g., for a point and
 a corresponding label.
 The random seed is reset after jittering.
-If `NA` (the default value), the current random seed is used.
+If `NA` (the default value), the seed is initialised with a random value;
+this makes sure that two subsequent calls start with a different seed.
 Use `NULL` to use the current random seed and also avoid resetting
 (the behavior of \pkg{ggplot} 2.2.1 and earlier).}
 }

From f222cfcc1e1be5ff0d8eaa650eb13bf58d920374 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Tue, 7 Feb 2017 14:18:33 +0100
Subject: [PATCH 13/17] extract with_preserve_seed()

---
 R/utilities.r | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/R/utilities.r b/R/utilities.r
index 5cb065de79..4a01235745 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -300,14 +300,22 @@ find_args <- function(...) {
 dummy_data <- function() data.frame(x = NA)
 
 with_seed <- function(seed, code) {
-  if (!is.null(seed)) {
-    old_seed <- get_valid_seed()
-    on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
-    if (is.na(seed)) {
-      seed <- sample.int(2147483647L, 1L)
-    }
-    set.seed(seed)
+  if (is.null(seed)) {
+    code
+  } else {
+    with_preserve_seed({
+      if (is.na(seed)) {
+        seed <- sample.int(2147483647L, 1L)
+      }
+      set.seed(seed)
+      code
+    })
   }
+}
+
+with_preserve_seed <- function(code) {
+  old_seed <- get_valid_seed()
+  on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
   code
 }
 

From 7715aa797000261528e783c37b3e1603d2e63ed0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Tue, 7 Feb 2017 14:21:23 +0100
Subject: [PATCH 14/17] extract function

---
 R/utilities.r | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/R/utilities.r b/R/utilities.r
index 4a01235745..1a4ad7a745 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -304,10 +304,7 @@ with_seed <- function(seed, code) {
     code
   } else {
     with_preserve_seed({
-      if (is.na(seed)) {
-        seed <- sample.int(2147483647L, 1L)
-      }
-      set.seed(seed)
+      set_seed(seed)
       code
     })
   }
@@ -333,6 +330,13 @@ get_seed <- function() {
   get0(".Random.seed", globalenv(), mode = "integer")
 }
 
+set_seed <- function(seed) {
+  if (is.na(seed)) {
+    seed <- sample.int(2147483647L, 1L)
+  }
+  set.seed(seed)
+}
+
 # Needed to trigger package loading
 #' @importFrom tibble tibble
 NULL

From 7774c657bfad009ab64abcd22072d7b42c66b37c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Thu, 16 Feb 2017 21:03:55 +0100
Subject: [PATCH 15/17] use withr

---
 DESCRIPTION         |  5 ++++-
 R/position-jitter.r |  6 +++++-
 R/utilities.r       | 34 ++--------------------------------
 3 files changed, 11 insertions(+), 34 deletions(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index f2426e8422..40f350b03f 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -16,13 +16,14 @@ Imports:
     digest,
     grid,
     gtable (>= 0.1.1),
+    lazyeval,
     MASS,
     plyr (>= 1.7.1),
     reshape2,
     scales (>= 0.4.1),
     stats,
     tibble,
-    lazyeval
+    withr
 Suggests:
     covr,
     ggplot2movies,
@@ -41,6 +42,8 @@ Suggests:
     rpart,
     rmarkdown,
     svglite
+Remotes:
+    jimhester/withr
 Enhances: sp
 License: GPL-2 | file LICENSE
 URL: http://ggplot2.tidyverse.org, https://github.com/tidyverse/ggplot2
diff --git a/R/position-jitter.r b/R/position-jitter.r
index 6b8350b299..3d136d7691 100644
--- a/R/position-jitter.r
+++ b/R/position-jitter.r
@@ -46,6 +46,10 @@
 #'   geom_point(position = jitter) +
 #'   geom_point(position = jitter, color = "red", aes(am + 0.2, vs + 0.2))
 position_jitter <- function(width = NULL, height = NULL, seed = NA) {
+  if (!is.null(seed) && is.na(seed)) {
+    seed <- sample.int(.Machine$integer.max, 1L)
+  }
+
   ggproto(NULL, PositionJitter,
     width = width,
     height = height,
@@ -72,6 +76,6 @@ PositionJitter <- ggproto("PositionJitter", Position,
     trans_x <- if (params$width > 0) function(x) jitter(x, amount = params$width)
     trans_y <- if (params$height > 0) function(x) jitter(x, amount = params$height)
 
-    with_seed(params$seed, transform_position(data, trans_x, trans_y))
+    with_seed_null(params$seed, transform_position(data, trans_x, trans_y))
   }
 )
diff --git a/R/utilities.r b/R/utilities.r
index 1a4ad7a745..36f0ea0485 100644
--- a/R/utilities.r
+++ b/R/utilities.r
@@ -299,44 +299,14 @@ find_args <- function(...) {
 # global data
 dummy_data <- function() data.frame(x = NA)
 
-with_seed <- function(seed, code) {
+with_seed_null <- function(seed, code) {
   if (is.null(seed)) {
     code
   } else {
-    with_preserve_seed({
-      set_seed(seed)
-      code
-    })
+    withr::with_seed(seed, code)
   }
 }
 
-with_preserve_seed <- function(code) {
-  old_seed <- get_valid_seed()
-  on.exit(assign(".Random.seed", old_seed, globalenv()), add = TRUE)
-  code
-}
-
-get_valid_seed <- function() {
-  seed <- get_seed()
-  if (is.null(seed)) {
-    # Trigger initialisation of RNG
-    runif(1L)
-    seed <- get_seed()
-  }
-  seed
-}
-
-get_seed <- function() {
-  get0(".Random.seed", globalenv(), mode = "integer")
-}
-
-set_seed <- function(seed) {
-  if (is.na(seed)) {
-    seed <- sample.int(2147483647L, 1L)
-  }
-  set.seed(seed)
-}
-
 # Needed to trigger package loading
 #' @importFrom tibble tibble
 NULL

From d0bf7016c4623108e45d611aea835c16e3778c64 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Fri, 14 Jul 2017 10:03:39 +0200
Subject: [PATCH 16/17] move entry to NEWS.md

---
 NEWS    | 3 ---
 NEWS.md | 2 ++
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/NEWS b/NEWS
index 54284565c7..12746fc39f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,3 @@
-* `position_jitter()` gains a `seed` argument that allows specifying a random
-  seed for reproducible jittering (#1996, @krlmlr).
-
 ggplot2 1.0.1
 ----------------------------------------------------------------
 
diff --git a/NEWS.md b/NEWS.md
index aba915e5de..18e02dfcc6 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -104,6 +104,8 @@
 
 * `ggproto()` produces objects with class `c("ggproto", "gg")`. This was added so that when layers, scales, or other ggproto objects are added together, an informative error message is raised (@jrnold, #2056).
 
+* `position_jitter()` gains a `seed` argument that allows specifying a random seed for reproducible jittering (#1996, @krlmlr).
+
 
 ### sf
 

From bc38d7372bcd72a6c11acee5b02193ec6457f9aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krlmlr+r@mailbox.org>
Date: Fri, 14 Jul 2017 10:38:24 +0200
Subject: [PATCH 17/17] add withr as remote

---
 DESCRIPTION | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 627edcf616..a019b3312b 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -48,7 +48,8 @@ Suggests:
     viridisLite
 Remotes:
     hadley/scales,
-    hadley/svglite
+    hadley/svglite,
+    jimhester/withr
 Enhances: sp
 License: GPL-2 | file LICENSE
 URL: http://ggplot2.tidyverse.org, https://github.com/tidyverse/ggplot2